Vacuum debulk and radiation cure system and apparatus

ABSTRACT

A system for fabricating a composite item from a layup may comprise a debulking device, a vacuum generator and a curing device. The debulking device may include a vacuum chamber, an envelope and a heater. The vacuum chamber may have a chamber pressure. The envelope may be contained within the vacuum chamber and may have an envelope pressure. The layup may be received within the envelope. The heater may heat the layup. The vacuum generator may be in fluid connection with the debulking device. The curing device may cure the layup.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of and claimspriority to pending U.S. application Ser. No. 11/357,017 filed on Feb.21, 2006, now issued as U.S. Pat. No. 7,842,209, and entitled VACUUMDEBULK AND RADIATION CURE SYSTEM APPARATUS AND METHOD, the entirecontents of which is expressly incorporated by reference herein.

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

(Not Applicable)

FIELD

The present disclosure relates generally to a debulking and radiationcuring device. More particularly, the present disclosure pertains to avacuum assisted debulking and radiation curing system and device.

BACKGROUND

Laminated materials such as, for example, composites are widely utilizedto increase structural rigidity in a wide variety of products. Forexample, composites are increasingly utilized by the airplaneconstruction industry to build airframes, structural members ofairframes, wings, wing spars, and the like. In some of the most advancedaircraft, where high strength and rigidity and low weight are extremelyimportant, composites may account for a significant portion of theairframe as well as the external surface or skin.

Typically, these composites are constructed from a plurality of layersplaced over a form. These layers are often referred to as partial orfull plies. Each ply may be in the form of unidirectional fibermaterial, woven fibers in a fabric, braided, metal foils, or a varietyof other conformations. In general, the unidirectional material, suchas, “tape” may be place in any arbitrary orientation or angle. Plies oftape are often placed in several directions or strand orientations suchas, 0°, 90°, ±45°, and the like. The fibers may be made from any of amultitude of natural and/or “man-made” materials such as fiberglass,graphite, Kevlar®, and the like.

To fabricate a composite item, a “layup” of plies is placed in or on aform or mandrel. These plies may be saturated or pre-impregnated with aresin such as epoxy. This epoxy may be cured or hardened in a variety ofways depending upon the particular epoxy system utilized. If anyinternal voids are present in the layup, these voids may adverselyaffect the cured composite item.

To minimize any voids present, the plies of the layup are typicallyplace upon the mandrel with a roller that exerts a great deal ofcompaction force. Even with this compaction, some voids may remain. Inaddition, some resin systems may generate gasses as they are heatedand/or during curing. While conventional methods and devices have beenemployed to overcome these issues, these conventional solutions have notbeen fully successful.

Accordingly, it is desirable to provide a system, apparatus and methodfor debulking a composite layup that is capable of overcoming thedisadvantages described herein at least to some extent.

BRIEF SUMMARY

The above-noted needs associated with composite layups are addressed bythe system and apparatus disclosed herein. In an embodiment, disclosedis a system for fabricating a composite item from a composite layup. Thesystem may comprise a debulking device, a vacuum generator and a curingdevice. The debulking device may include a vacuum chamber, an envelopeand a heater. The vacuum chamber may have a chamber pressure. Theenvelope may be contained within the vacuum chamber and may have anenvelope pressure. The layup may be received within the envelope. Theheater may heat the layup. The vacuum generator may be in fluidconnection with the debulking device. The curing device may cure thelayup

Also disclosed is an apparatus for fabricating a composite item from alayup of composite material. The apparatus may comprise a means fordegassing, a means for debulking and a means for curing. The means fordegassing may include a means for reducing an envelope pressure withinan envelope containing the layup, a means for reducing a chamberpressure within a vacuum chamber containing the envelope and a means forheating the layup.

The means for debulking the layup may include a means for increasing thechamber pressure relative to the envelope pressure such that theenvelope exerts a compressive force upon the layup in response to therelatively higher chamber pressure relative to the envelope pressure.The means for curing the layup may expose the layup to radiation togenerate the composite item.

Further disclosed is a system for fabricating a composite item from alayup including at least one ply of composite material and a radiationcurable resin. The system may comprise a mandrel for receiving thelayup, a debulking device and an emitter. The mandrel may receive thelayup. The debulking device may include a vacuum chamber having achamber pressure, a vacuum generator in fluid connection with the vacuumchamber and a valve disposed between the vacuum chamber and the vacuumgenerator for controlling vacuum pressure within the vacuum chamber.

The debulking device may further include an envelope contained withinthe vacuum chamber and having an envelope pressure. The layup may bereceived within the envelope. The vacuum generator may be fluidconnection with the envelope. A valve may be disposed between theenvelope and the vacuum generator for controlling vacuum pressure withinthe envelope. The heater may heat the layup and may comprise at leastone a heating element and/or an infrared heater. The emitter may curethe layup. The emitter may emit an electron beam, ultraviolet radiationand/or X-ray radiation.

The features, functions and advantages that have been discussed can beachieved independently in various embodiments of the present disclosureor may be combined in yet other embodiments, further details of whichcan be seen with reference to the following description and drawingsbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the present disclosure will become moreapparent upon reference to the drawings wherein like numerals refer tolike parts throughout and wherein:

FIG. 1 is a block diagram of a vacuum debulking system according to anembodiment of the disclosure;

FIG. 2 is a cross-sectional view of a vacuum debulking device suitablefor use with the vacuum debulking system according to FIG. 1;

FIG. 3 is a cross-sectional view of a mandrel suitable for use with thevacuum debulking system according to FIG. 1; and

FIG. 4 is a flow diagram illustrating steps that may be followed inaccordance with an embodiment of the method or process.

DETAILED DESCRIPTION

The present disclosure provides a vacuum debulking system and device foruse with radiation curable resin systems. In some embodiments, thevacuum debulking system facilitates degassing and debulking a compositelayup that demonstrates a marked improvement over conventional systemsfor use with radiation curable resin systems. The layup includes atleast one ply of composite material with a radiation curable resin. Thevacuum debulking system includes a gas-tight or substantiallygas-impermeable membrane that covers or envelopes the layup.

In response to a pressure differential across the membrane, compressiveforce is exerted upon the layup. This process is typically referred toas “vacuum bagging” even though a “bag” or envelope may or may not beutilized. The vacuum debulking system further includes a vacuum chamber.By placing the vacuum bagged layup in the vacuum chamber and drawing avacuum in both the vacuum bagged layup and the vacuum chamber,atmospheric pressure on the layup may be reduced. Reducing theatmospheric pressure facilitates degassing the resin. This degassingprocess may be further enhanced by reducing the viscosity of the resin.Depending upon the resin system utilized, the resin viscosity may bereduced by heating, for example.

Following degassing, the atmosphere within the vacuum chamber isincreased or allowed to come to ambient pressure while the vacuum withinthe envelope is maintained. In this manner, the layup may be compressedor debulked via the action of the atmospheric pressure acting upon theenvelope. This method reduces or eliminates any bubbles or voids withinthe layup utilizing any suitable resin system. Suitable resin systemsinclude radiation curable thermoset resins, and the like. It is aparticular advantage of embodiments of the disclosure that resins curedvia electron beam (“EB”) processing may be utilized.

These EB cured resins exhibit material properties and processingcharacteristics that may be advantageous in relatively high technologyapplications such as, for example, aerospace, racing, sports equipment,and the like. Some particular advantages of radiation curable resinsinclude: Low residual stresses compared to thermally cured composites;Ability to co-cure metallic components with composite material due tothe low residual stresses; Ability to fabricate truly asymmetricstructures without part warpage during cure; Lower cost tooling due tolower cure temperatures and pressures; Lower cost tool design becausethere does not need to be compensation for cure-induced dimensionalvariation; Does not require autoclaves; Radiation curable resins andadhesives have very long working and shelf lives at room temperaturemeasured in years, not days. Radiation curable resins and adhesives donot require freezers for storage and the long working life allows thefabrication of very large and/or complex structures.

Fabricating EB cured composites is typically achieved without the use ofan autoclave to achieve their greatest benefit. However, conventionalmethods for degassing and debulking the layups are difficult and timeconsuming. In addition, these conventional methods produce parts withonly moderate quality and limited robustness. As such, the structuralproperties of conventionally fabricated composite items areunsatisfactory when made with EB cured resins. Advantages of variousembodiments of the disclosure include: (1) facilitates out gassing ofresins; and (2) decreasing occurrences of air pockets within thereinforcement and/or between the reinforcement and mandrel.

The disclosure will now be described with reference to the drawingfigures, in which like reference numerals refer to like partsthroughout. As shown in FIG. 1, a vacuum debulking system 10 includes avacuum debulking device 12 to degas and compress a layup 14. The vacuumdebulking device 12 includes a mandrel 16, heater 18, envelope 20, andvacuum chamber 22. The mandrel 16 includes a surface upon which thelayup 14 is placed and provides a mold to which the layup 14 may conformto.

In operation, the layup 14 and envelope 20 may be disposed within thevacuum chamber 22. For example, the vacuum chamber 22 may be placed uponand sealed to the mandrel 16. In another embodiment, the vacuum chamber22 is disposed upon a surface 24 and sealed with a sealant 26. To debulkthe layup 14, the layup 14 is compressed upon the mandrel 16 in responseto a pressure differential across the envelope 20. This pressuredifferential is generated when an interior of the envelope 20 is at arelatively lower pressure than an exterior of the envelope 20. Forexample, a vacuum generator 28 in fluid connection with the envelope 20may be configured to remove a portion of air and/or gasses from theenvelope 20. If a pressure (“P_(chamber)”) within the vacuum chamber 22is greater than a pressure (“P_(envelope)”) within the envelope 20, theenvelope 20 may exert a compressive force (“F_(c)”) upon the layup 14that varies according to the difference between the P_(envelope) and theP_(chamber).

The vacuum chamber 22 facilitates controlling the F_(e). In general, thevacuum chamber 22 is disposed to cover at least that portion of theenvelope 20 that covers the layup 14. In a particular example, thevacuum chamber 22 is disposed to cover the layup 14, mandrel 16, heater18, and envelope 20. The vacuum chamber 22 is in fluid communicationwith a vacuum generator 30 that may be controlled to remove a portion ofthe atmosphere outside of the envelope 20. By maintaining theP_(chamber) at or below the P_(envelope), the F_(c) may be reduced oreliminated.

In this manner, the layup 14 may be degassed. In this regard, the heater18 is configured to impart thermal energy upon the layup 14 and therebyfacilitate the egress of any gas from the layup 14. The heater 18 mayinclude any suitable heating device such as, for example, a heatingelement, infra red (IR) heater, oven, and the like. The vacuum debulkingdevice 12 optionally includes one or more valve such as valves 32 and34. If present, the valves 32 and 34 are configured to control theamount of vacuum pressure within the envelope 20 and vacuum chamber 22.

According to various embodiments, the layup 14 includes a radiationcurable resin and/or a thermoset type resin. Generally, the viscosity ofthese resin systems is reduced, initially, by an increase intemperature. Radiation curable resins are, as the name implies, “cured”by exposure to radiation such as, for example, electron beam (“EB”),X-ray, ultraviolet, and the like. The curing process solidifies theresin via an essentially irreversible chemical polymerization reaction.In this regard, the layup 14 may be cured 36 via exposure to an emitter38. As a result of the debulking and any curing procedures, a compositeitem 40 is generated. The composite item 40 includes any suitable itemor part such as, for example, “C-channels” and other structural members,wing spars, fuselage frames, panels, and the like.

FIG. 2 is a cross-sectional, view of the vacuum debulking device 12suitable for use with the vacuum debulking system 10. As shown in FIG.2, the vacuum debulking device 12 includes the layup 14 and the mandrel16. In addition, the vacuum debulking device 12 includes parting films50A and 50B, bagging film 52, sealant 54, vacuum port 56, exit breather58, and an optional caul plate 60.

The parting films 50A and 50B include any suitable release film or peelply operable to reduce adhesion of the cured item 40 to the variousother components of the vacuum debulking device 12. Generally, suitableparting films include those that do not appreciably adhere to the layup14. Suitable parting films may facilitate a flow of air there through soas to facilitate the degassing and debulking processes. In a particularexample, the parting films 50A and 50B are Teflon® coated wovenfiberglass layers such as Armalon®. As shown in FIG. 2, the parting film50A is disposed to cover at least a portion of the layup 14. Also shownin FIG. 2, the parting film 50B is disposed to cover at least someportion of the exit breather 58 and may extend under the layup 14.

The caul plate 60 is optionally included to facilitate modification ofsurface characteristics. If present, the caul plate 60 may include arelatively stiff or rigid material having a lower surface that is drawntoward an upper surface of the reinforcement. In this manner, the uppersurface of the reinforcement may be modified to essentially correspondto the lower surface of the caul plate 60.

The bagging film 52 is a gas tight or essentially gas impermeablemembrane to facilitate generating a pressure differential. That is, whensealed upon the mandrel 16, the bagging film 52 forms the envelope 20(See FIG. 1) enclosing the layup 14 and, to a sufficiently large extent,prevents air and/or gasses from passing there through. Generally, thebagging film 52 includes any suitably impermeable membrane, layer, orbarrier. Suitable materials from which the bagging film may be madeinclude plastics, rubbers, resins, metals, and the like. Air and/orother gasses drawn from the envelope 20 generates a pressuredifferential that exerts a compressive force upon the contents of theenvelope 20.

The sealant 54 facilitates generating a gas tight or substantially gasimpermeable seal between the bagging film 52 and the mandrel 16. Invarious embodiments, the sealant 54 includes any suitable sealingmaterial and/or method. Examples of suitable sealing materials and/ormethods includes sticky, tacky and other such adhesive tapes or cordage,heat sealing, elastomeric seals, and the like. In other embodiments, thesealant 54 is optional and may be omitted. For example, the vacuum film46 may include a bag, reusable bag, or other such envelope that thelayup 14 and/or mandrel 16 is placed in.

The vacuum port 56 facilitates removal of some or all of the atmospherefrom the envelope 20. For example, the vacuum port 56 may be fluidlyattached to the vacuum generator 28. In this manner, air and/or othergasses may be drawn out from within the envelope 20 by the vacuumgenerator 28.

The exit breather 58 facilitates removal of the atmosphere from theenvelope 20 by increasing the surface area from which gasses are removedvia the vacuum port 56. In a particular example, the exit breather 58includes a porous fabric, woven fiberglass tape, metal or ceramicmaterial.

To reduce any likelihood of resin being drawn into the exit breather 58,the vacuum debulking device 12 includes a choke zone 62 or other suchregion disposed between the layup 14 and the exit breather 58. The layup14 is held back from the choke zone 62. To facilitate movement of airand/or gasses from the layup 14 to the exit breather 58, the partingfilm 50B is placed to extend across the choke zone 62 and cover most orall of the exit breather 58.

Also shown in FIG. 2, the vacuum chamber 22 includes a port 64 in fluidconnection to the vacuum generator 30. By modulating the P_(chamber)relative to the P_(envelope), a force (F_(bf)) exerted by the baggingfilm 52 upon the layup 14 may be controlled. For example, by modulatingthe P_(chamber) to essentially coincide with the P_(envelope), theF_(bf) may be substantially zero. In another example, by maintaining anegative pressure differential or negative Δ pressure of the P_(chamber)relative to the P_(envelope), the bagging film 52 may be drawn away fromthe layup 14 to generate an out gassing pocket 66. In this regard, theP_(envelope) is essentially equal to a pressure within the out gassingpocket 66 (P_(pocket)). By modulating the P_(chamber) relative to theP_(envelope) (e.g., P_(pocket)) to generate a positive Δ pressure, thelayup 14 may be compressed or debulked.

The out gassing pocket 66 provides a volume for any out gassed productsand/or provides some “head space” for bubbles, which rise to the surfaceof the resin during out gassing, to break in.

The mandrel 16 may include a layup zone 68 to provide a surface, uponwhich, the layup 14 may be disposed. The layup zone 68 may be configuredto correspond to a surface of the item 40. In addition, the layup zone68 may be surfaced as appropriate. For example, a release coating may beapplied to the layup zone 68 to facilitate removal of the item 40. Inanother example, the layup zone 68 may be polished or otherwise surfacedto facilitate layup and/or release of the item 40.

To prepare the vacuum debulking device 12 for operation, the variouscomponents of the vacuum debulking device 12 are positioned, one uponthe other in a manner similar to that illustrated in FIG. 2. Inoperation, the vacuum debulking device 10 includes the gas tightenvelope 20 (See FIG. 1) that surrounds the layup 14 and various layers.Gasses are drawn from the envelope 20 via the exit breather 58 and fromthe vacuum chamber 22 via the port 64. The layup 14 is heated via theheater 18 and any gasses present in the layup 14 may escape from thelayup 14 to accumulate in the out gassing pocket 66 and/or may be drawnout of the envelope 20 via the exit breather 58. Upon sufficient outgassing, air may be allowed to enter the port 64 in response tomodulation of the valve 34, for example. As air enters the vacuumchamber 22, the Δ pressure is increased, thereby increasing the F_(bf)to debulk the layup 14.

FIG. 3 is a cross-sectional view of the mandrel 16 suitable for use withthe vacuum debulking system 10 according to FIG. 1. The mandrel 16 ofFIG. 3 is similar to the mandrel 16 of FIG. 2, and thus, in the interestof brevity, those items described in FIG. 2, will not be described againin FIG. 3. As shown in FIG. 3, the mandrel 16 includes the layup zone 68that corresponds to the item 40. More particularly, the item 40 is a “C”channel and the layup zone 68 includes a female mold that corresponds tothe “C” channel profile. In addition, the vacuum debulking device 12includes an alternative vacuum port 56 in the bagging film 52. Inoperation, the bagging film vacuum port 56 or the mandrel vacuum port 56may be utilized.

FIG. 4 illustrates steps involved in a method 80 of debulking the layup14 to fabricate the item 40. Prior to the initiation of the method 80,the item 40 is designed and a series of computer readable instructionsspecifying attributes of the composite product is generated. Theseinstructions are utilized to generate the mandrel 16. In addition, thevarious components of the vacuum debulking system 10 are gathered andprepared for the process. Furthermore, the mandrel 16 may be preparedfor the debulking process by applying a release coating to any surfacesthat may come into contact with the layup 14. In addition, vacuum linesmay be attached to the vacuum port 56 and vacuum generator 28, and thelike.

In general, at step 82, the vacuum debulking system 10 is firstprepared. Then, at step 84, the layup 14 is degassed and, at step 86,the layup 14 is debulked. More particularly, at step 88, the layup ispositioned. In general, positioning the layup includes positioning theplies of composite material that make up the layup 14 and the variousother layers on or in the mandrel 16 as shown in FIGS. 2 and 3. Theplies may include fabric, unidirectional, and/or non-woven fibrousmaterial, metal foils, and the like. The material of the fibers mayinclude glass, carbon, quartz, Kevlar®, polymers, aramid, and/or othersuch fibers.

In addition, the plies may include strips that are, themselves, wovenprior to or during placement on the mandrel 16. These plies may bepre-impregnated with any suitable resin. In addition, the parting films50A and/or 50B are positioned. For example, the parting film 50A isdisposed upon the layup 14 and the parting film 40 B is disposed upon ata least a portion of the exit breather 58. The parting film 50B mayadditionally be disposed upon some portion of the mandrel 16 interveningbetween the layup zone 68 and the exit breather 58.

Optionally, at step 88, the caul plate 60 is positioned. If utilized,the caul plate 60 is disposed relatively above the layup 14 and tends toreduce surface irregularities. In addition, the caul plate 60 may beutilized to impart a predetermined surface feature. In other instances,the caul plate 60 does not appreciably reduce surface irregularities,and thus, may be omitted.

At step 90, the layup 14 is sealed within the envelope 20. For example,the sealant 54 and the bagging film 52 are positioned. Moreparticularly, a sticky, tacky, or adhesive ribbon or cord-like materialmay be disposed about a perimeter of the mandrel 16. Thereafter, thebagging film 52 may be disposed to extend to or beyond the sealant 54.tstep 92, the vacuum chamber 22 is positioned. For example, the vacuumchamber 22 may be positioned upon the surface 24 so as to cover thelayup 14 and/or mandrel 16.

At step 94, the vacuum chamber 22 may be sealed. For example, a sticky,tacky, or adhesive ribbon or cord-like material or rubber gasket may bedisposed about a perimeter of the vacuum chamber 22.

To degas the layup 14, the pressure is reduced and the viscosity of theresin is reduced. More particularly, at step 96, the vacuum generators28 and/or 30 may withdraw a portion of the air and/or gas from theenvelope 20 and/or the vacuum chamber 22. Optionally, the vacuumpressure may be modulated to generate a slight negative Δ pressure andthereby generate the out gassing pocket 66. The vacuum generator 28and/or 30 may be configured to reduce the chamber pressure P_(chamber)below the envelope pressure P_(chamber) prior to the heater 18 heatingthe layup 14 to the degassing temperature and reduce the envelopepressure P_(chamber) below chamber pressure P_(chamber) prior to acuring device heating the layup 14.

At step 98, the layup 14 may be heated. For example, the heater 18 mayapply sufficient heat to the layup 14 to reduce the viscosity of theresin. The reduced P_(envelope) and/or P_(chamber) may be held for aperiod of time sufficient to degas the layup 14. For example, the vacuumchamber 22 may be transparent to facilitate viewing the layup 14. Uponcessation of bubbling activity, the out gassing procedure may becompleted. In addition, a specific “recipe” of time, temperature, andpressures may be used. This “recipe” may be specific to the materialand/or material/part combination.

Following degassing, the layup 14 may be debulked at step 100. Accordingto an embodiment, the Δ pressure is modulated to debulk the layup 14.For example, the P_(chamber) may be raised to generate a positive Δpressure. In a particular example, the valve 34 may be modulated to stopor reduce the flow of air from the vacuum chamber 22 to the vacuumgenerator 30 and the valve 34 may be further modulated to allow acontrolled amount of air into the vacuum chamber 22. By controlling theΔ pressure, the rate of debulking may be controlled.

At step 102, the debulked item 40 is optionally removed from the chamber22. For example, the chamber 22 may be removed to facilitate curing theitem 40. In another example, the vacuum debulking device 12 may be leftintact and, at step 108, the item may be cured while in the chamber 22.In such instances, the chamber 22 may include a radiation transparentportion or window to facilitate exposing the item 40 to radiation or theemitter 38 may be disposed within the chamber 22.

At step 104, it is determined whether the temperature of the layup 14 isappropriate for the curing procedure. Depending upon the resin systemand curing method, it may be optimal to cure the layup 14 at atemperature that is relatively higher or lower than the degassingtemperature. Accordingly, at step 104, the temperature of the layup issensed and it determined if the temperature is within a predeterminedcuring temperature range. For example, if it is determined that thetemperature of the layup 14 is relatively greater than a predeterminedmaximum temperature, the layup 14 may be cooled or allowed to cool atstep 106. If it is determined that the temperature of the layup 14 isrelatively less than a predetermined minimum curing temperature, thelayup 14 may be heated at step 106.

At step 106, the temperature of the layup 14 is modulated in response tothe sensed temperature being outside the predetermined curingtemperature range. More particularly, the layup 14 is cooled in responseto the sensed temperature being relatively higher than the predeterminedmaximum curing temperature or the layup 14 is heated in response to thesensed temperature being relatively less than the predetermined minimumcuring temperature. The predetermined maximum and minimum temperaturesmay be based upon a variety of factures such as, for example, resinmanufacturers' recommendations, thickness of the layup 14, compositionof the layup 14, empirical data, and the like.

At step 108, the layup 14 is cured to generate the item 40. Variousresin formulations employ a variety of methods for chemical hardening orpolymerization. For example, a group of resins broadly classified asradiation curable resins are cured by exposure to radiation such as EB,X-rays, ultra violet, and the like. To cure the layup 14, the layup 14may be introduced to a beam of radiation via a conveyer belt, forexample. In another example, the emitter 38 may be passed over and/oraround the layup 14. In these or other such manners, sufficientradiation is applied the layup 14 in a controlled manner to facilitate achemical reaction or polymerization of the resin in the layup 14.

Following the method 80, the item 40 may be removed from the vacuumdebulking device 12 and parted from the layup. Optionally, the item 40may be finished. Finishing may encompass sanding, polishing, milling,cleaning, or the like.

The many features and advantages of the disclosure are apparent from thedetailed specification, and thus, it is intended by the appended claimsto cover all such features and advantages of the disclosure which fallwithin the true spirit and scope of the disclosure. Further, sincenumerous modifications and variations will readily occur to thoseskilled in the art, it is not desired to limit the disclosure to theexact construction and operation illustrated and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the disclosure.

What is claimed is:
 1. A system for fabricating a composite item from alayup, comprising: a mandrel for receiving the layup; a debulking deviceincluding: a vacuum chamber having a chamber pressure; an envelopecontained within the vacuum chamber and having an envelope pressure, theenvelope receiving the layup; and a heater heating the layup to adegassing temperature; and a vacuum generator in fluid connection withthe envelope through the vacuum port formed in the mandrel and in fluidcommunication with the vacuum chamber; the vacuum generator beingconfigured to reduce the chamber pressure below the envelope pressureprior to the heater heating the layup to the degassing temperature andreduce the envelope pressure below the chamber pressure prior to acuring device curing the layup.
 2. The system according to claim 1wherein the heater comprises at least one of the following: a heatingelement, an infrared heater.
 3. The system according to claim 1, furthercomprising: an exit breather for fluid connection to the vacuumgenerator.
 4. The system according to claim 1, further comprising: avalve disposed between the vacuum chamber and the vacuum generator forcontrolling a vacuum pressure within the vacuum chamber.
 5. The systemaccording to claim 1, further comprising: a valve disposed between theenvelope and the vacuum generator for controlling a vacuum pressurewithin the envelope.
 6. A system for fabricating a composite item from alayup including radiation curable resin, comprising: a mandrel forreceiving the layup and having a vacuum port formed therein and a chokezone located on the mandrel between the layup and the vacuum port in themandrel; a debulking device including: a vacuum chamber having a chamberpressure; a vacuum generator in fluid connection with the vacuumchamber; a valve disposed between the vacuum chamber and the vacuumgenerator for controlling a vacuum pressure within the vacuum chamber;an envelope contained within the vacuum chamber and having an envelopepressure, the envelope receiving the layup and being in fluidcommunication with the vacuum generator through the vacuum port formedin the mandrel; a valve disposed between the envelope and the vacuumgenerator for controlling a vacuum pressure within the envelope; and aheater to heat the layup to a degassing temperature and comprising atleast one of a heating element and an infrared heater; and an emitterconfigured to cure the radiation curable resin by heating the layup to atemperature that is lower than the degassing temperature, the emitteremitting at least one of the following: an electron beam, ultravioletradiation, X-ray radiation; the vacuum generator being configured toreduce the chamber pressure below the envelope pressure prior to theheater heating the layup to the degassing temperature and reduce theenvelope pressure below the chamber pressure prior to a curing deviceheating the layup; and the choke zone reducing resin draw into thevacuum port formed in the mandrel.
 7. The system according to claim 1,further comprising: the curing device configured to heat the layup to acuring temperature.
 8. The system according to claim 7, wherein thecuring device comprises: an emitter.
 9. The system according to claim 8,wherein the emitter is disposed within the vacuum chamber.
 10. Thesystem according to claim 8, wherein the emitter is disposed exterior tothe vacuum chamber.
 11. The system according to claim 10, wherein thevacuum chamber is configured to facilitate exposure of the layup toradiation through a radiation transparent portion of the vacuum chamber.12. The system according to claim 8, wherein the emitter is movablerelative to the layup to cure the layup.
 13. The system according toclaim 8, wherein the emitter emits at least one of the following: anelectron beam, ultraviolet radiation, X-ray radiation.